So I’ve rebuilt my original block with new rod bearings, piston rings, and fresh heads. Got everything installed and to my surprise I still have a knock. Swapped the injectors around and it went away for a bit. Ordered rebuilt injectors and that put me back to where it all started. No knock when the engine is cold but comes on when warm. So it is safe to say it’s not mechanical but more a spark knock or pre detonation.
Things of note,
Got a bank 1 lean code after a bit of driving.
Also got a SAI insufficient flow code another time.
Knock sensor voltage is above 3v on cyl. 6 during knock
In troubleshooting the SAI, I discovered that if I run the SAI output tests and start the car the knock is gone for a few minutes. I did this half a dozen times and it worked every time. It appears the car is running lean when SAI is not on and causing the pre detonation. I don’t understand the link.
I’ve chased most of the vacuum lines and only found a leak in the intake actuator. Sealant is curing on that now.
Plugs are in great shape and I’ve moved the coils around but knock remained in cyl. 6.
I’m coming to quite the loss but currently pulling the SAI valves and giving them an ops check and cleaning.
I have no idea where to go from here or how to find out what’s causing the detonation. A/F ratios are a little off but not terrible in my opinion.